HBCU-Excellence in Research: Radiative Forcing Due to Carbon Dioxide and Black Carbon in Urban Areas

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It is well known that carbon dioxide (CO2) and black carbon are two potent climate drivers that absorb sunlight and play a critical role to influence the Earth's radiation budget and local/regional climate. Black carbon (BC) is also associated with human health problems such as respiratory and cardiovascular disease, and cancer. Thus, it is essential to know concentrations of CO2 and BC and have a clear understanding of direct radiative forcing (DRF) due to CO2 and black carbon at a city level. Current radiative forcing is estimated at a regional or global level due to limited concentration measurements of CO2 and BC. The objective of this study is to examine temporal variations of CO2 and BC at one urban site and develop a unique approach to estimate radiative forcing at a city level. The findings from this project will help better understand larger uncertainties in climate change prediction by various climate models. Also, this research exposes both graduate and undergraduate students to real-life environmental problems and provides them great opportunities to learn quantitative skills used in the fields of environmental science. This will in turn help increase the number of minority students who will pursue STEM degrees.In this project, one Multifilter Rotating Shadowband Radiometer (MFR-7) will be used to measure total, diffuse, and direct irradiance at six wavelengths at one urban site and one ObservAir® sensor will be used to monitor BC, carbon monoxide and carbon dioxide concentrations. Mobile measurements will be conducted at one urban site and one rural site six times per day weekly using 5-wavelength UV-IR Black Carbon monitor (microAeth® MA200). Also, one Air Quality Particle Counting Meter will be used to provide measures of 6 sizes of particles. Then the Santa Barbara Discrete Ordinate (DISORT) model will be used to retrieve optical and microphysical parameters including single scatter albedo(SSA) and asymmetry parameter with the inclusion of MODIS imagery. The next step involves the estimation of CO2 radiative forcing and the calculation of aerosol radiative forcing using Santa Barbara DISORT Atmospheric Radiative Transfer(SBDART) model at a city level and different seasons. This research will allow better characterization of aerosol optical and microphysical parameters including single scattering albedo and asymmetry parameter at a city level, which could help understand large uncertainties in estimates of DRF used for many climate models. Also, a new method on estimation of DRF will be developed in order to estimate DRF at a city level.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.